import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;

public class Demo_Callable {
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        Callable<Integer> callable = new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                int sum = 0;
                for(int i = 1; i <= 1000; i++){
                    sum += i;
                }
                return sum;
            }
        };
        FutureTask futureTask = new FutureTask(callable);
        Thread t = new Thread(futureTask);
        t.start();
        t.join();
        System.out.println(futureTask.get());
    }
}
